/**
 * @Author 12629
 * @Description：
 */
public class MyLinkedList {

    static class ListNode {
        public int val;
        public ListNode next;
        public ListNode prev;

        public ListNode(int val) {
            this.val = val;
        }
    }

    public ListNode head;
    public ListNode last;

    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        if(head == null) {
            head = node;
            last = node;
        }else {
            node.next = head;
            head.prev = node;
            head = node;
        }
    }


    public void addLast(int data) {
        ListNode node = new ListNode(data);
        if(head == null) {
            head = node;
            last = node;
        }else {
            last.next = node;
            node.prev = last;
            last = node;
        }
    }

    public void addIndex(int index, int data) {
        int len = size();
        // 检查index是否合法
        if(index < 0 || index > len) {
            //可以抛出自定义的异常
            System.out.println("index位置不合法："+index);
            return;
        }
        if(index == 0) {
            addFirst(data);
            return;
        }
        if(index == len) {
            addLast(data);
            return;
        }
        ListNode cur = findIndex(index);
        ListNode node = new ListNode(data);
        node.next = cur;
        cur.prev.next = node;
        node.prev = cur.prev;
        cur.prev = node;
    }

    private ListNode findIndex(int index) {
        ListNode cur = head;
        while (index != 0) {
            cur = cur.next;
            index--;
        }
        return cur;
    }




    public boolean contains(int key) {
        ListNode cur = head;
        while (cur != null) {
            if(cur.val == key) {
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    public void remove(int key) {
        ListNode cur = head;
        while (cur != null) {
            if(cur.val == key) {
                if(cur == head) {
                    head = head.next;//head == null
                    if(head == null) {
                        last = null;
                    }else {
                        head.prev = null;
                    }
                }else {
                    cur.prev.next = cur.next;
                    if(cur.next == null) {
                        last = last.prev;
                    }else {
                        cur.next.prev = cur.prev;
                    }
                   /* if(cur == last) {

                    }else {

                    }*/
                }
                return;
            }else {
                cur = cur.next;
            }
        }
    }

    public void removeAllKey(int key) {
        ListNode cur = head;
        while (cur != null) {
            if(cur.val == key) {
                if(cur == head) {
                    head = head.next;//head == null
                    if(head == null) {
                        last = null;
                    }else {
                        head.prev = null;
                    }
                }else {
                    cur.prev.next = cur.next;
                    if(cur.next == null) {
                        last = last.prev;
                    }else {
                        cur.next.prev = cur.prev;
                    }
                }
            }
            cur = cur.next;
        }
    }

    public int size() {
        ListNode cur = head;
        int count = 0;
        while (cur != null) {
            count++;
            cur = cur.next;
        }
        return count;
    }

    public void clear() {
      /* ListNode cur = head;
        while (cur != null) {
            ListNode tmp = cur.next;
            //cur.val = null;
            cur.prev = null;
            cur.next = null;
            cur = tmp;
        }*/
        head = null;
        last = null;
    }


    public void display() {
        ListNode cur = head;
        while (cur != null) {
            System.out.print(cur.val+" ");
            cur = cur.next;
        }
        System.out.println();
    }
}
